Is all your traffic going through the VPN? You can bind the VPN in the torrent client so that only torrent traffic goes through the VPN, while other traffic does not. This way, you should be able to connect to your local network.
Reading their other comments, i think they are not using a real number/a number they don't have access to, and signal is requiring to verify it/ "secure it" after the update. Thus, even tho the messages are stored locally they can't access it without doing something with the number
Is all your traffic going through the VPN? You can bind the VPN in the torrent client so that only torrent traffic goes through the VPN, while other traffic does not. This way, you should be able to connect to your local network.